Protector



W. L. COOK.

PROTECTOR.

APPLICATION FILED MAY 3, 1919.

1 A3512 1 3 Patented Nov. 14, 1922.

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W. L. COOK.

PROTECTOR.

APPLICATION HLED MAYB,1919. 1,4352 1 3 atented Nov, 14, 1922.

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Patent ed Nov. 14, 1922 WALLACE L. COOK, OF CHICAGO, ILLINOIS.

PROTECTOR.

Application filed Kay 8, 1919.

To all whom it may concern:

Be it known that I, VVALLAQE L. COOK, a citizen of the United States, residin at Chicago, in the county of Cook and btate of Illinois, have invented a certain new and useful Improvement in Protectors, of which the following is a full, clear, concise, and exact description, reference beinghad to the accompanying drawings. forming a part of this specification.

My invention relates to protectors and more particularly to protectors of the type known as lightning or high potential arresters. In protectors such as cable protectors, telephone and telegraph protectors,

switch-board protectors or the like, the lightning arresters have usually taken the form of two solid conducting blocks of carbon, which are removably connected to the line and ground terminals, respectively of the circuit or apparatus to be protected, these blocks being held apart by an interposed strip of insulation. This strip is cut or per orated so as to provide an open space cut-out for the passage of the discharge from one block to the ground block to thus protect the apparatus to be protected against high potential currents. such. for instance, as the direct current five hundred volt trolley current. The incoming wires associated with the protectors and which are the wires that may become charged with the high potential are usually connected to the lightning arresters afterhaving passed through fuses. The open space cut-out above referred to between the blocks is delicately adjusted to break down on five hundred volts direct current so that a discharge may take place, for instance, if one of the line wires become crossed with a trolley circuit. The establishment of the arc across the air gap generally increases current flow so that the fuse is blown thus interrupting the flow of the current through the protectors.

In many cases the air gap above referred to must be no greater than five one-thousandths of an inch. The maintenance of this slight gap presents many difficulties and annoyances. The separators between the arrester blocks are loose and merely held in place by the tension of the springs which hold the blocks. Displacement of these insulators is thus very frequent thereby causing the arrester blocks to become short circuited so as to establish aground upon the Serial No. 295,651.

line. Carbon arrester blocks also have a tendency to dust, and metal blocks to blister on static and other discharges which likewise cause grounds.

For the reasons outlined such carbon arrestel's are continually giving trouble even though no high potential voltages have been upon the line. The troublemen or maintainers who have custody of such devices in actual use are therefore frequently found to increase the number of separators between the discharge blocks so as to avoid these grounds. Such action of course destroys the eiliciency of the arrester although it does prevent many accidental grounds. Frequently troublemen or maintainers remove the discharge blocks altogether when they clear a ground so as to avoid future trips to clear grounds whereby the plant or instruments are left without protection against high potential discharges. Protectors of the saw tooth adjustable air gap type as shown in Patent No. 1,122,575, issued to myself and George V. Rodormer, December 29. 1914, avoid most of the objectionable features enumerated above, but are not adaptable to switch-boards and cable protectors or to many other protectors of similar types, because they cannot be mounted in a sufficiently confined space. In rotectors which use two solid discharge locks, the blocks are readily removable; they represent a very small proportion of the cost of the entire protector equipment with which they are associated, but their tendency to cause permanent grounds on the lines destroys not only their efliciency but the efliciency of the entire protector.

My invention contemplates adapting the self-clearing saw tooth or similarly constructed arrester for use in protectors so that it may be mounted upon close centers. In constructing the arresters of my invention, I arrange them of such form that they can be used in existing protector units.

My improved protectors are so designed that they are not subject to the frailties above enumerated in connection with protectors of the prior art and their absence to cause grounds upon the line makes it possible to operate equipment Without interruptions to the service and thus greatly improve the efficiency of such protectors. The readily removability of the arresters of my invention increases their effectiveness.

My invention avoids the difiiculties as fia above outlined in connection'with the loose makes it possible to provide arrester equipment which may operate on a very low voltage break-down.

In accordance with my invention, 1 provide as one element of the arrester a serrated or saw tooth or similar structure which is placed in close proximity to the other element. T find that such a saw tooth or similar element will generally maintain an are for a sun'icient length of time to blow the fuse and will then clear itself.

Such a saw tooth or similar element will not become accidentally grounded due to dust particles and the arrangement of my improved structure is such that there is no danger of accidental displacement of the insulation whereby a ground. may be or.- casioned. My improved device furthermore is of such a character that a space is provided between the saw tooth portion and its carrier so dust particles are prevented from settling into a position where they might ground the lines.

My invention concerns itself also with the provision of a device of this character which is of such construction that the air gap will be maintained to the proper thousandth of an inch as may be required for the particular instruments involved.

1 will explain one form which my invention may take more in detail by referring to the accompanying drawings, in which-- Fig. 1 is a side view of one form of protective device in which my improved arrester may find application;

Fig. 21 is a sectional view on line 2-2 01?- Fig. 1;

Fig. 3 is an enlarged sectional view of the structure shown in Figs. 1 and 2, tragmerr tary in form to illustrate my improved protector; v

Fig. 1 is a perspective view of the insulating mounting of my protector element;

Fig. 5 is a sectional view on line 5-5 of Fig. 3;

Fig. 6 is a side view of the protective element shown in Fig. 5;

Fig. 7 is a sectional view of a punch and die illustrating the manner of forming my improved protective element;

Fi 8 is a sectional view on line 88 of Fig. ,and

Fig. 9 is a fragmentary longitudinal sectional view of my protector element showing an added feature.

Referring more particularly to Figs. 1 and 2, it show a customary form of pole top cable terminal having a suitable base plate 10 to which strips 11, 11 are mounted which carry protectors, these protectors consisting of the fuses 12 and my improved lightning arresters 13.

The lightning arrester construction of my invention is more clearly illustrated in Figs. 3, 4, 5 and 6. In the preferred form as here shown the lightning arrester construction contemplates the use of two arrester elements, one of which is the old and well known carbon ground element 14 which operates in co-operative relation with the other element 15, the element 15 constituting the structure of my invention, The element 15 includes a metallic serrated element 16 preferably U-shaped wherever it is desired to have two serrated edges. The U-shaped element 16 has the two arms 17, 17, the lower edges of which are serrated to form teeth 18, which teeth are the proper distance away from the ground element 14 when the two mates 14 and 15 are in co-operative relation. The element 16 is fixedly mounted upon an insulating base plate 19 shown more clearly in Fig. a, this base plate 19 having holes 20 into which fingers 21 punched out of the material of the element 16 are forced, to hold the parts 16 and 19 securely together. The edges of the teeth 18 terminate short of the lower line of the insulating base plate 19 so that the proper air gap exists between the teeth 18 and thecarbon 14. The material constituting the spark element 16 is suiticiently strong so that it will not be bent under any conceivable force that may be applied to it during its proper use. For this reason the air gap is always of the proper length.

It will be also noted that the legs 17 of the U-shaped element 16 do not hug the sides of the insulating elementclosely, but that a suitable space 22 is left. This space prevents the accumulation of dust which might cause a grounding or short circuit between the teeth 18 and the carbon block 14.

The device is thus selficleaning in its nature. l i hen the two mates are placed together ready for insertion in the device they are pressed between the two holding springs 23 and 24.

My invention further contemplates the accurate setting of the extremities of the teeth 18 relatively to the lower surface of the insulating base plate 19. In manufacturing the device I prefer to fixedly secure the spark element 16 to the insulating base 19 and then place the entire structure between a suitable punch and die which are shown in Fig. 8, the punch being shown at 25 and the die at 26. The die is so arranged that the legs 17 of the elements 16 rest upon little step-like portions 27 elevated the proper amount above the bottom wall 28 of the die. The punch has a resiliently carried movable holding element .29 which first engages the top of the spark element 16 as the punch is moving downwardly, thus to hold the parts engages the bottom wall 28 ot' the die. This leaves impressions 31 (Fig. 3), when the fingers have actuated the metallic portion of the element 16. Thus by virtue of these depressions the position of the insulating base 1%) relative to the spark element 16 is maintained. Each and every device is thus accurately set so that the base of the teeth 18 are the proper distance backwardly from the base line of the insulating element 1!). As before stated, the entire element 1?) is sufficiently rigid so that its structure is maintained intact in the course of any ordinary usage. It will of course be apparent that it is immaterial what mate is used in connection with my improved arrester element. the drawings merely showing its connection with the customary carbon element 141-.

In Fig. 9, I show my improved protector element as provided with a plug of solder 32 which is designed to melt and cause a permanent electrical contact between the finger 21 and the ground plate it whenever the arc is continued a sufiicient length of time to heat the arrester beyond a predetermined amount. The short circuiting ot' the elements 21 and 14 will be then a positive as surance that the fuse blows to thereby open the circuit, and protect the apparatus against the high potential.

In the claims I use the words ground plate as indicative of any kind or character of mate which may be used in connection with my improved protective element.

It will also be apparent that many modifications may be made from the device as herein disclosed without departing from its spirit. llaving however thus described one form which my invention may take, what I claim as new and desire to secure by Letters Patent is l. A high potential protector comprising a ground plate and a cooperating protector device consisting of a U-shaped conducting element and an insulatingelement secured together and set in permanent relationship so that when said device and plate are juxtaposed with the insulating element abutting said plate. said conducting element and plate form a spark gap of predetermined length between them, the legs of said conducting element being spaced from said insulating element to prevent the accumulation of foreign matter at their active extremities.

2. A high potential protector comprising a ground plate and a co-operating protector device comprising a conducting element, and an interposed insulating element, said conducting element being provided with a portion adapted to engage said insulating element and having a portion extending substantially at right angles thereto provided with a serrated free edge portion forming a multiplicity of discharge points spaced both laterally and longitudinally from all other portions of said protector.

3. As a new article of manufacture a protector element adapted to co-operate with a ground plate, comprising as a unitary structure, a U shaped conducting element, and an insulating element within said conducting element, thebight portion of said U shaped element being provided with indentations adapted to engage the adjacent face of said insulating element, said indentations being of such proportions relative to the insulating element that said elements are set in definite relationship to provide an air gap of predetermined length between said plate and element, regardless of slight variations in the size of said insulating element.

4. A device of the character described, a removable protector comprising a metallic member having a serrated edge portion, spaced from all portions of said device, a block of conducting material and an insulating element interposed between said block and said metalli'cmember, conducting holding means engaging said block and metallic member on opposite faces of said protector and abutment s for preventing lateral shifting of said removable protector relative to said holding means.

5. As a new article of manufacture a readily removable protector element adapted to cooperate with a ground plate, comprising as a unitary structure aconducting element having a serrated active extremity and an insulating element secured to said conducting element, said conducting element being provided with indentations engaging said insulating element whereby the parts are held in definite relationship to establish an air gap of predetermined length between said plate and element when juxtaposed regardless of any variations in the size of said insulating element.

6. As a new article of manufacture a protector element adapted to cooperate with a ground plate. comprising as a unitary structure a conductor element and an insulating element set in definite relationship to establish an air gap of predetermined length between said plate and element when juxtaposed, said insulating element having holes and said conducting element having fingers forced into said holes whereby the two parts are fixedly held together.

7. As a new article of manufacture a protector element adapted to cooperate with a ground plate. comprising as a unitary structure a conducting element and an insulating element set in definite relationship to establish an air gap of predetermined length between said plate and element when juxtaposed, said conducting element at its active extremity being spaced from said insulating element to prevent the accumulation of foreign matter at said active extremity, said insulating element having holes and said conducting element having fingers forced into said holes whereby the two parts are fixedly held together.

8. As a new article of manufacture a protector element adapted to cooperate with a ground plate comprising as a unitary structure a U-shaped conducting element having two serrated active extremities, and an insulating element set in definite relationship by a formation on said conducting element that engages said insulating element, said formation being so proportioned as to compensate for any slight variations in size of said insulating element toestablish an air gap of predetermined length between said plate and said element when juxtaposed.

9. As a new article of manufacture a protector element adapted to cooperate with ground plate, comprising as a unitary structure a U-shaped conducting element having two serrated active extremities and an insulating element set in definite relationship to establish an air gap of predetermined length between said plate and element when juxtaposed, said insulating element having holes and said conducting element having fingers forced into said holes whereby the two parts are fixedly held together.

'10. As a new article of manufacture a protector element adapted to cooperate with a ground plate, comprising as a unitary structure a U-shaped conducting element having two serrated active extremities and an insulating element set in definite relationship to establish an air gap of predetermined length between said plate and element when juxtaposed, said conducting element at its active extremity being spaced fromsaid insulating element to prevent the accumulation of foreign matter at said active extremity, said insulating element having holes and said conducting element having fingers inane forced into said holes whereby the two parts i 12. A. protector of the character described comprising a pair of substantially parallel metallic fingers, and a pair of arrester elements removably held in cooperative relationship by said fingers, said fingers extending lengthwise of said elements and one of said arrester elements consisting of a piece of metal having a serrated edge.

13. in a device of the character described,

an arrester element, means for demountably carrying said arrester element and means for preventing displacement of said arrester' element transverse to its length, said arrester element comprising a conducting element having a serrated edge portion, and means for insulatingly supporting said conducting element, the serrated edge of said element being laterally spaced from said supporting means, said conducting element embracing said supporting means, and being provided with means engaging said supporting means for holding said conducting element and supporting means'in definite relationship.

14. A protector comprising a ground element, a U-shaped metallic element having serrations formed along its edges, and an insulating element positioned between the legs of said U-shaped element and maintaining said serrated edges in definite relationship with said ground element, the legs of said U-shaped element being spaced from the sides of said insulating element.

in witness whereof, I hereunto subscribe my name this 30th day of April, A. D, 1919.

WALLACE lb. COOK. 

